Reading a bit more on it, it's starting to sound less practical to me. Almost more like a differential, in that you have to supply a variable speed to one shaft to change the ratio. Now that's easy enough with an electric motor, but if that auxiliary input requires significant torque, it's not so useful anymore.<p>Several people have commented that it sounds very much like some of the hydrostatic drives used in the Agri industries.<p>But hey, it's still a neat demonstration, if not entirely practical.
I'll be honest in that I can't quite figure out how this works. I did note the acentric gear at end which would be very difficult to balance and would surely put huge loads on the shaft holding it. From the text it sounds like the ratio is selected by spinning the lower shaft at a variable speed, which is quite interesting but sounds like a bit of a challenge.